Autoinjector triggered by skin contact

ABSTRACT

An autoinjector includes a case adapted to hold a medicament container having a needle telescopically coupled to the case and movable between a first extended position relative to the case in which the needle is covered and a retracted position relative to the case in which the needle is exposed. The autoinjector includes a plunger rotationally and slidably disposed in the case rotatable relative to the case between a first rotational position in which the plunger is engaged to the case and a second rotational position in which the plunger disengages the case engages the plunger to rotate the plunger from the first rotational position to the second rotational position when the needle shroud translates from the first extended position to the retracted position. The autoinjector includes a cap removably coupled to the case includes at least one compliant case beam adapted to releasably engage at least one aperture in the case.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national stage application under 35 USC §371of International Application No. PCT/EP2015/056686, filed on Mar. 27,2015, which claims priority to European Patent Application No.14162454.4, filed on Mar. 28, 2014, the entire contents of which areincorporated herein by reference.

TECHNICAL FIELD

This disclosure relates to an autoinjector.

BACKGROUND

Administering an injection is a process which presents a number of risksand challenges for users and healthcare professionals, both mental andphysical. Injection devices typically fall into two categories—manualdevices and autoinjectors. In a conventional manual device, manual forceis required to drive a medicament through a needle. This is typicallydone by some form of button/plunger that has to be continuously pressedduring the injection. There are numerous disadvantages associated withthis approach. For example, if the button/plunger is releasedprematurely, the injection will stop and may not deliver an intendeddose. Further, the force required to push the button/plunger may be toohigh (e.g., if the user is elderly or a child). And, aligning theinjection device, administering the injection and keeping the injectiondevice still during the injection may require dexterity which somepatients (e.g., elderly patients, children, arthritic patients, etc.)may not have.

Autoinjector devices aim to make self-injection easier for patients. Aconventional autoinjector may provide the force for administering theinjection by a spring, and trigger button or other mechanism may be usedto activate the injection. Autoinjectors may be single-use or reusabledevices.

There remains a need for an improved autoinjector.

SUMMARY

Certain aspects of the present invention provide an improvedautoinjector.

In an exemplary embodiment an autoinjector according to one aspect ofthe invention comprises:

-   -   a case adapted to hold a medicament container having a needle;    -   a needle shroud telescopically coupled to the case and movable        between a first extended position relative to the case in which        the needle is covered and a retracted position relative to the        case in which the needle is exposed; and    -   a plunger rotationally and slidably disposed in the case, the        plunger rotatable relative to the case between a first        rotational position in which the plunger is engaged to the case        and a second rotational position in which the plunger disengages        the case,    -   wherein the needle shroud engages the plunger to rotate the        plunger from the first rotational position to the second        rotational position when the needle shroud translates from the        first extended position to the retracted position, the        auto-injector further comprising:    -   a cap removably coupled to the case, wherein the cap includes at        least one compliant case beam adapted to releasably engage at        least one aperture in the case.

In an exemplary embodiment, when the cap is moved in the distaldirection relative to the case, the at least one compliant beamdisengages the at least one aperture in the case and no longer radiallyabuts the case.

In an exemplary embodiment the needle shroud is movable to a secondextended position relative to the case in which the needle is coveredand the needle shroud cannot translate relative to the case.

In an exemplary embodiment the cap includes an element adapted to engagea protective needle sheath removably disposed on the needle.

In an exemplary embodiment the cap includes at least one compliant beamadapted to releasably engage at least one radial aperture in the needleshroud.

In an exemplary embodiment, when the cap is coupled to the case, the atleast one compliant beam engages the at least one radial aperture in theneedle shroud and radially abuts the case.

In an exemplary embodiment, when the cap is removed from the case, theat least one compliant beam disengages the at least one radial aperturein the needle shroud and no longer radially abuts the case.

In an exemplary embodiment the autoinjector further comprises a shroudspring biasing the needle shroud in a distal direction relative to thecase.

In an exemplary embodiment a force required to disengage the at leastone compliant case beam from the respective aperture is greater than aforce exerted by the shroud spring when the compliant case beam isengaged in the aperture.

In an exemplary embodiment the autoinjector further comprises a drivespring biasing the plunger in a distal direction relative to the case.

In an exemplary embodiment the plunger translates relative to the caseunder force of the drive spring when the plunger is in the secondrotational position and the needle shroud is in the retracted position.

In an exemplary embodiment the plunger is at least partially hollow andthe drive spring is at least partially disposed within the plunger.

In an exemplary embodiment the needle shroud includes at least onecompliant shroud beam radially abutting the case when the needle shroudis in the first extended position and the retracted position, whereinthe at least one compliant shroud beam deflects radially when the needleshroud is in the second extended position and axially abuts the case.

In an exemplary embodiment the plunger includes a first plunger bossadapted to engage a shroud rib disposed on the needle shroud and asecond plunger boss adapted to engage a case slot in the case.

In an exemplary embodiment, when the plunger is in the first rotationalposition and the needle shroud is in the first extended position, thefirst plunger boss engages the shroud rib and the second plunger bossengages the case slot.

In an exemplary embodiment, when the needle shroud is in the retractedposition, the plunger rotates from the first rotational position to asecond rotational position and disengages the case slot.

In an exemplary embodiment the plunger includes a plunger boss adaptedto engage a case slot in the case, and a plunger rib adapted to engage ashroud rib disposed on the needle shroud.

In an exemplary embodiment, when the plunger is in the first rotationalposition and the needle shroud is in the first extended position, theplunger boss engages the case slot.

In an exemplary embodiment, when the needle shroud translates from thefirst extended position to the retracted position, the needle shroudabuts the plunger rib to rotate the plunger relative to the case fromthe first rotational position to a second rotational position todisengage the plunger boss from the case slot.

In an exemplary embodiment, the cap comprises:

-   -   a distal face;    -   at least one compliant sheath removal beam extending in a        proximal direction from the distal face and defining a space for        receiving the protective needle sheath, the at least one        compliant sheath removal beam including at least one ledge        adapted to engage the protective needle sheath,    -   wherein the at least one compliant sheath removal beam is        disposed approximately perpendicular to the distal face in a        first position for engaging the protective needle sheath and is        disposed at a non-approximately perpendicular angle to the        distal face in a second position for receiving the protective        needle sheath.

The cap is suitable for being applied with any kind of injection deviceor autoinjector.

In an exemplary embodiment the at least one compliant sheath removalbeam is biased toward the first position.

In an exemplary embodiment the ledge is adapted to engage proximallybehind a proximal end of the protective needle sheath or into a recesswithin the protective needle sheath.

In an exemplary embodiment the cap further comprises one or more lateralapertures arranged in distal face of the cap or in a lateral area of thecap to allow insertion of at least one assembling tool for applying aforce to move the at least one compliant sheath removal beam from thefirst position to the second position.

The sheath removal mechanism allows for engaging the protective needlesheath during assembly. When the cap is removed from the case of themedicament delivery device in preparation of an injection the sheathremoval mechanism pulls out the protective needle sheath reliablywithout exposing the user to too high a risk to injure themselves. Thesheath removal mechanism is suited for removing a protective needlesheath even if the protective needle sheath is arranged far behind anorifice of the medicament delivery device making it impossible to begripped manually. Thus the needle can be arranged in the case initiallya distance back from the orifice in order to prevent the user fromtouching the tip of the needle after the protective needle sheath isremoved.

Further scope of applicability of certain aspects of the presentinvention will become apparent from the detailed description givenhereinafter. However, it should be understood that the detaileddescription and specific examples, while indicating exemplaryembodiments of the invention, are given by way of illustration only,since various changes and modifications within the spirit and scope ofthe invention will become apparent to those skilled in the art form thisdetailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain aspects of the present invention will become more fullyunderstood from the detailed description given hereinbelow and theaccompanying drawings which are given by way of illustration only, andthus, are not limitive of the present invention, and wherein:

FIG. 1A is a longitudinal section of an exemplary embodiment of anautoinjector according to certain aspects of the present inventionduring assembly,

FIG. 1B is a schematic side view of an exemplary embodiment of anautoinjector according to certain aspects of the present inventionduring assembly,

FIG. 2 is a schematic view of an exemplary embodiment of a shroud lockmechanism of an exemplary embodiment of an autoinjector according tocertain aspects of the present invention,

FIG. 3 is a perspective exploded view of an exemplary embodiment of acontrol subassembly of an exemplary embodiment of an autoinjectoraccording to certain aspects of the present invention,

FIG. 4 is a perspective exploded view of an exemplary embodiment of adrive subassembly of an exemplary embodiment of an autoinjectoraccording to certain aspects of the present invention,

FIG. 5 is a perspective view of an exemplary embodiment of a needlesheath removal mechanism of an exemplary embodiment of an autoinjectoraccording to certain aspects of the present invention,

FIG. 6 is a schematic view of an exemplary embodiment of a plungerrelease mechanism of an exemplary embodiment of an autoinjectoraccording to certain aspects of the present invention,

FIG. 7 is a schematic view of an exemplary embodiment of a plungerrelease mechanism of an exemplary embodiment of an autoinjectoraccording to certain aspects of the present invention during assembly,

FIG. 8 is a schematic view of an exemplary embodiment of a plungerrelease mechanism of an exemplary embodiment of an autoinjectoraccording to certain aspects of the present invention after assembly,

FIG. 9 is a schematic view of an exemplary embodiment of a shroud lockmechanism of an exemplary embodiment of an autoinjector according tocertain aspects of the present invention after assembly,

FIG. 10 is a schematic view of an exemplary embodiment of shroud lockmechanism of an exemplary embodiment of an autoinjector according tocertain aspects of the present invention during assembly,

FIG. 11 is a schematic view of an exemplary embodiment of shroud lockmechanism of an exemplary embodiment of an autoinjector according tocertain aspects of the present invention during assembly,

FIG. 12 is a schematic view of an exemplary embodiment of shroud lockmechanism of an exemplary embodiment of an autoinjector according tocertain aspects of the present invention during assembly,

FIG. 13 is a schematic view of an exemplary embodiment of shroud lockmechanism of an exemplary embodiment of an autoinjector according tocertain aspects of the present invention during assembly,

FIG. 14 is a schematic view of an exemplary embodiment of shroud lockmechanism of an exemplary embodiment of an autoinjector according tocertain aspects of the present invention after assembly,

FIG. 15A is a longitudinal section of an exemplary embodiment of anautoinjector according to certain aspects of the present invention afterassembly,

FIG. 15B is a schematic side view of an exemplary embodiment of anautoinjector according to certain aspects of the present invention afterassembly,

FIG. 16 is a schematic view of an exemplary embodiment of a shroud lockmechanism an exemplary embodiment of an autoinjector according tocertain aspects of the present invention prior to use,

FIG. 17A is a longitudinal section of an exemplary embodiment of ashroud lock mechanism an exemplary embodiment of an autoinjectoraccording to certain aspects of the present invention prior to use,

FIG. 17B is a schematic side view of an exemplary embodiment of a shroudlock mechanism an exemplary embodiment of an autoinjector according tocertain aspects of the present invention prior to use,

FIG. 18A is a longitudinal section of an exemplary embodiment of anautoinjector according to certain aspects of the present inventionduring use,

FIG. 18B is a schematic side view of an exemplary embodiment of anautoinjector according to certain aspects of the present inventionduring use,

FIG. 19 is a schematic view of an exemplary embodiment of a plungerrelease mechanism of an exemplary embodiment of an autoinjectoraccording to certain aspects of the present invention during use,

FIG. 20A is a longitudinal section of an exemplary embodiment of anautoinjector according to certain aspects of the present inventionduring use,

FIG. 20B is a schematic side view of an exemplary embodiment of anautoinjector according to certain aspects of the present inventionduring use,

FIG. 21A is a longitudinal section of an exemplary embodiment of anautoinjector according to certain aspects of the present invention afteruse,

FIG. 21B is a schematic side view of an exemplary embodiment of anautoinjector according to certain aspects of the present invention afteruse,

FIG. 22 is a schematic view of an exemplary embodiment of a shroud lockmechanism of an exemplary embodiment of an autoinjector according tocertain aspects of the present invention after use,

FIGS. 23A-E is a schematic view of another exemplary embodiment of aplunger release mechanism before, during and after use,

FIGS. 24A-B are different schematic longitudinal sections of anotherexemplary embodiment of the autoinjector,

FIG. 25A is a schematic view of a distal end of an exemplary embodimentof an autoinjector according to certain aspects of the present inventionduring assembly,

FIG. 25 B is a schematic view of an exemplary embodiment of a cap to beattached to an auto-injector,

FIG. 26 is a schematic view of the distal end of the autoinjector withthe assembled cap during insertion of a wedge shaped assembly toolthrough an aligned set of lateral apertures,

FIG. 27 is a schematic view of the distal end of the autoinjector withthe assembled cap and the inserted assembly tool during assembly of amedicament container with a protective needle sheath, and

FIG. 28 is a schematic view of the distal end of the autoinjector withthe assembled cap, medicament container and protective needle sheath.

Corresponding parts are marked with the same reference symbols in allfigures.

DETAILED DESCRIPTION

FIG. 1A is a longitudinal section of an exemplary embodiment of anautoinjector 1 according to certain aspects of the present inventionduring assembly. The autoinjector 1 comprises a case 2 comprising afront case 2.1 and a rear case 2.2. The case 2 is adapted to hold amedicament container, such as a syringe 3. The syringe 3 may be apre-filled syringe and have a needle 4 arranged at a distal end. Whenthe autoinjector 1 and/or the syringe 3 are assembled, a protectiveneedle sheath 5 may be removably coupled to the needle 4. The protectiveneedle sheath 5 may be a rubber needle sheath or a rigid needle sheath(which is composed of rubber and a full or partial plastic shell). Astopper 6 is arranged for sealing the syringe 3 proximally and fordisplacing a medicament M contained in the syringe 3 through the needle4. In other exemplary embodiments, the medicament container may be acartridge which includes the medicament M and engages a removable needle(e.g., by threads, snaps, friction, etc.).

In an exemplary embodiment, a cap 11 may be removably disposed at adistal end of the case 2. The cap 11 may include an element (e.g., abarb, a hook, a narrowed section, etc.) arranged to engage theprotective needle sheath 5, the case 2 and/or a needle shroud 7telescoped within the case 2. The cap 11 may comprise grip features 11.5for facilitating removal of the cap 11 (e.g., by twisting and/or pullingthe cap 11.5 relative to the case 2).

In an exemplary embodiment, a shroud spring 8 is arranged to bias theneedle shroud 7 in a distal direction D against the case 2.

In an exemplary embodiment, a drive spring 9 is arranged within the case2. A plunger 10 serves for forwarding a force of the drive spring 9 tothe stopper 6. In an exemplary embodiment, the plunger 10 is hollow andthe drive spring 9 is arranged within the plunger 10 biasing the plunger10 in the distal direction D against the case 2. In another exemplaryembodiment, the plunger 10 may be solid and the drive spring 9 mayengage a proximal end of the plunger 10. Likewise, the drive spring 9could be wrapped around the outer diameter of the plunger 10 and extendwithin the syringe 3.

In an exemplary embodiment, a plunger release mechanism 12 is arrangedfor preventing release of the plunger 10 prior to retraction of theneedle shroud 7 relative to the case 2 and for releasing the plunger 10once the needle shroud 7 is sufficiently retracted.

In an exemplary embodiment, a first shroud lock mechanism 14 is arrangedto prevent retraction of the needle shroud 7 relative to the case 2 whenthe cap 11 is in place, thereby avoiding unintentional activation of theautoinjector 1 (e.g., if dropped, during shipping or packaging, etc.).The first shroud lock mechanism 14 may comprise one or more compliantbeams 11.3 on the cap 11 and a respective number of apertures 7.6 in theneedle shroud 7 adapted to receive each of the compliant beams 11.3.When the cap 11 is attached to the autoinjector 1, the compliant beams11.3 abut a radial stop 2.15 on the case 2 which prevents the compliantbeams 11.3 from disengaging the apertures 7.6. When the cap 11 isattached to the autoinjector 1, axial movement of the cap 11 in theproximal direction P relative the case 2 is limited by a rib 11.4 on thecap 11 abutting the case 2. When the cap 11 is pulled in the distaldirection D relative to the case 2, the compliant beams 11.3 may abut anedge of the aperture 7.6 and deflect to disengage the aperture 7.6,allowing for removal of the cap 11 and the protective needle sheath 5attached thereto. In an exemplary embodiment, the compliant beams 11.3and/or the apertures 7.6 may be ramped to reduce force necessary todisengage the compliant beams 11.3 from the apertures 7.6.

FIG. 1B is a schematic side view of an exemplary embodiment of theautoinjector 1 according to certain aspects of the present inventionduring assembly. In the exemplary embodiment in FIG. 1B, the case 2 isremoved for clarity. FIG. 1B and FIG. 2 show a second shroud lockmechanism 15 that is adapted to lock the needle shroud 7 in an axialposition relative to the case 2 after the autoinjector 1 has beenremoved from the injection site. In an exemplary embodiment, the secondshroud lock mechanism 15 comprises at least one compliant shroud beam7.1 on the needle shroud 7 adapted to proximally abut a stop 2.12 on thecase 2 after the autoinjector 1 has been removed from the injectionsite. The abutment of the shroud beam 7.1 on the stop 2.12 preventstranslation of the needle shroud 7 in the proximal direction P relativeto the case 2. Prior to use, when the cap 11 is attached to theautoinjector 1, the cap 11 is adapted to engage and deflect thecompliant shroud beam 7.1 radially inward, allowing the shroud beam 7.1to pass the stop 2.12 in the proximal direction P so that the needleshroud 7 can translate in the proximal direction P relative to the case2.

In an exemplary embodiment, the autoinjector 1 may formed from at leasttwo subassemblies, e.g., a control subassembly 1.1 and a drivesubassembly 1.2, to allow for flexibility as to the time and location ofmanufacture of the subassemblies 1.1, 1.2 and final assembly with thesyringe 3.

FIG. 3 is a perspective exploded view of an exemplary embodiment of acontrol subassembly 1.1 of an autoinjector 1 according to certainaspects of the present invention. In an exemplary embodiment, thecontrol subassembly 1.1 comprises the cap 11, the needle shroud 7, theshroud spring 8 and the front case 2.1. To assemble the controlsubassembly 1.1, the shroud spring 8 is inserted into the needle shroud7, and the needle shroud 7 with the shroud spring 8 is inserted into thefront case 2.1. The cap 11 is arranged over the distal end of the needleshroud 7.

FIG. 4 is a perspective exploded view of an exemplary embodiment of adrive subassembly 1.2 of an autoinjector 1 according to certain aspectsof the present invention. In an exemplary embodiment, the drivesubassembly 1.2 the plunger 10, the drive spring 9 and the rear case2.2. Those of skill in the art will understand that if the viscosity orvolume, for example, of the medicament M in the syringe 3 is changed,only parts of the drive subassembly 1.2 may need to be changed. Toassemble the drive subassembly 1.2, the drive spring 9 is inserted intothe plunger 10 and the plunger 10 is inserted in the rear case 2.2 inthe proximal direction P thereby compressing the drive spring 9. Oncethe plunger 10 and the drive spring 9 reach a compressed position it isrotated by an angle, e.g. approximately 30° relative to the rear case2.2, to engage the plunger 10 to the rear case 2.2. In an exemplaryembodiment, the rear case 2.2 may have a cam surface to engage theplunger 10 to induce this rotation prior to the plunger 10 and the drivespring 9 reaching the compressed position.

FIG. 5 is a perspective view of an exemplary embodiment of a needlesheath removal mechanism 13 of an autoinjector 1 according to certainaspects of the present invention. The needle sheath removal mechanism 13comprises an opening 11.1 axially arranged in the cap 11. The opening11.1 is approximately sized and shaped to receive the protective needlesheath 5. One or more bosses 11.2 may be disposed on a proximal end ofthe cap 11 and adapted to abut the protective needle sheath 5. Forexample, when the protective needle sheath 5 is inserted into theopening 11.1, the protective needle sheath 5 may deform around thebosses 11.2. The bosses 11.2 may be ramped to reduce force necessary toinsert the protective needle sheath 5 into the opening 11.1. Once theprotective needle sheath 5 has passed the bosses 11.2 in the distaldirection D, the bosses 11.2 may abut a proximal end of the protectiveneedle sheath 5 to prevent translation of the protective needle sheath 5in the proximal direction P relative to the cap 11. For example, duringremoval of the cap 11 from the autoinjector 1, the bosses 11.2 on thecap 11 may abut the proximal end of the protective needle sheath 5 andpush the protective needle sheath 5 in the distal direction D off of theneedle 4 with their non-ramped distal face. Those of skill in the artwill understand that a number of parameters can be varied, e.g. a radialheight of the boss 11.2, an axial length of the boss 11.2, an angle ofthe ramp of the boss 11.2, a durometer of the protective needle sheath5, a surface finish of the boss 11.2, etc., which could increase ordecrease assembly forces, cap removal forces, etc.

FIG. 6 is a schematic view of an exemplary embodiment of a plungerrelease mechanism 12 of the autoinjector 1 according to certain aspectsof the present invention during assembly. The plunger release mechanism12 is arranged for preventing release of the plunger 10 prior toretraction of the needle shroud 7 relative to the case 2 and forreleasing the plunger 10 once the needle shroud 7 is sufficientlyretracted. In an exemplary embodiment, the plunger release mechanism 12comprises the plunger 10, the rear case 2.2, and the needle shroud 7interacting with each other. In an exemplary embodiment, the needleshroud 7 is limited to axial movement relative to the case 2, and theplunger 10 can translate axially and rotate relative to the case 2.

In an exemplary embodiment, the plunger 10 comprises a first plungerboss 10.1 adapted to engage a shroud rib 7.7 on the needle shroud 7, asecond plunger boss 10.2 adapted to engage a case slot 2.3 in the case2, and a plunger rib 10.3 adapted to engage the shroud rib 7.7 on theneedle shroud 7. In an exemplary embodiment, the shroud rib 7.7comprises a proximal face 7.8 adapted to engage the plunger rib 10.3,and a distal face 7.9 and a longitudinal face 7.10 adapted to engage thefirst plunger boss 10.1. In an exemplary embodiment, the case slot 2.3comprises a first angled surface 2.9 adapted to apply a rotational forcein a first rotational direction R1 to the second plunger boss 10.2, awall 2.10 adapted to abut the second plunger boss 10.2 to limit rotationof the plunger 10 relative to the case 2 in the first rotationaldirection R1, and a second angled surface 2.11 adapted to apply arotational force in a second rotational direction R2, opposite the firstrotational direction R1, to the second plunger boss 10.2.

In an exemplary embodiment of an assembly process of the drivesubassembly 1.2, the plunger 10 with the drive spring 9 is inserted intothe rear case 2.2. When the second plunger boss 10.2 is axially alignedwith the case slot 2.3, the plunger 10 is rotated in the firstrotational direction R1 until the second plunger boss 10.2 is moved intothe case slot 2.3 until it abuts the wall 2.10. In this position, thefirst angled surface 2.9 prevents the second plunger boss 10.2 frommoving in the second rotational direction R2, and thus prevents theplunger 10 from rotating relative to the case 2.

After a syringe 3 (with the protective needle sheath 5 disposed on theneedle 4) is inserted into the control assembly 1.1, the drivesubassembly 1.2 is coupled to the control subassembly 1.1. In anexemplary embodiment, a pair of resilient beams 2.13 (shown in FIG. 1B)on the rear case 2.2 is adapted to snap into recesses 2.14 (shown inFIG. 3) in the front case 2.1 to lock the drive subassembly 1.2 to thecontrol subassembly 1.1. As the drive assembly 1.2 is coupled to thecontrol subassembly 1.1, the needle shroud 7 translates proximally(e.g., by use of an assembly jig) causing the shroud rib 7.7 to abut theplunger rib 10.3. As shown in FIG. 7, as the shroud rib 7.7 pushesplunger rib 10.3, the angle of the plunger rib 10.3 causes the plunger10 to rotate relative to the case 2 in the second rotational directionR2, and the second plunger boss 10.2 rides along the first angledsurface 2.9 onto the second angled surface 2.11. When the second plungerboss 10.2 is disposed on the second angled surface 2.11, the force ofthe drive spring 9 imparts a rotational force on the plunger 10 in thesecond rotational direction R2 due to the angle of the second angledsurface 2.11.

As shown in FIG. 8, when the needle shroud 7 is released (e.g., byremoving the assembly jig), the needle shroud 7 translates in the distaldirection D relative to the case 2 under the force the shroud spring 8until the shroud rib 7.7 abuts the first plunger boss 10.1. For example,the distal face 7.9 of the shroud rib 7.7 may abut the first plungerboss 10.1 and maintain the needle shroud 7 in an axial position relativeto the case 2. The second plunger boss 10.2 is prevented fromdisengaging the case slot 2.3, because the shroud rib 7.7 prevents theplunger 10 from rotating in the second rotational direction R2 relativeto the case 2. For example, the longitudinal face 7.10 of the shroud rib7.7 abuts the first plunger boss 10.1 to prevent rotation of the plunger10.

FIG. 9 shows an exemplary embodiment of the first shroud lock mechanism14 for an autoinjector 1 according to certain aspects of the presentinvention after assembly of the control subassembly 1.1. The compliantbeam 11.3 on the cap is engaged in the aperture 7.6 within the needleshroud 7. The radial stop 2.15 is axially spaced from the compliant beam11.3.

FIG. 10 shows an exemplary embodiment of the first shroud lock mechanism14 for an autoinjector 1 according to certain aspects of the presentinvention during insertion of the syringe 3 into the control subassembly1.1 for engaging the protective needle sheath 5 to the cap 11. Theaperture 7.6 provides some clearance allowing a movement of the needleshroud 7 relative to the cap 11 in the distal direction D. The frontcase 2.1 is also moved in the distal direction D relative to the cap 11axially aligning the radial stop 2.15 with the compliant beam 11.3preventing the cap 11 from disengaging the needle shroud 7.

FIG. 11 shows an exemplary embodiment of the first shroud lock mechanism14 for an autoinjector 1 according to certain aspects of the presentinvention, wherein after insertion of the syringe 3, the needle shroud 7is moved further in the proximal direction P relative to the front case2.1 by an assembly jig (not illustrated). In this state, the drivesubassembly 1.2 may be assembled to the control subassembly 1.1. Thecompliant beam 11.3 remains engaged in the aperture 7.6 and the radialstop 2.15 prevents them from disengaging.

After assembly of the drive subassembly 1.2 to the control subassembly1.1, the assembly jig is removed allowing the needle shroud 7 to moveback in the distal direction D relative to the front case 2.1 under theforce of the shroud spring 8 arriving again in the state illustrated inFIG. 10. In this configuration, the needle shroud 7 is prevented frommoving in the proximal direction P relative to the case 2, because theradial stop 2.15 prevents the compliant beam 11.3 from disengaging theaperture 7.6 and the rib 11.4 on the cap 11 proximally abuts the frontcase 2.1.

FIG. 12 shows an exemplary embodiment of the second shroud lockmechanism 15 for an autoinjector 1 according to certain aspects of thepresent invention after assembly of the control subassembly 1.1. Theneedle shroud 7 is partially inserted into the cap 11. The shroud beam7.1 is in a non-deflected position proximally abutting the stop 2.12 inthe front case 2.1. This prevents the needle shroud 7 from movingfurther in the proximal direction P relative to the front case 2.1 andkeeps the control subassembly 1.1 locked together.

FIG. 13 shows an exemplary embodiment of the second shroud lockmechanism 15 for an autoinjector 1 according to certain aspects of thepresent invention during insertion of the syringe 3 into the controlsubassembly 1.1, wherein the needle shroud 7 is moved further in thedistal direction D into the cap 11 such that the cap 11 radiallyinwardly deflects the shroud beam 7.1 out of its abutment with the stop2.12. The needle shroud 7 is thus free to move in the proximal directionP relative to the front case 2.1.

FIG. 14 shows an exemplary embodiment of the second shroud lockmechanism 15 for an autoinjector 1 according to certain aspects of thepresent invention after final assembly of the drive subassembly 1.2 tothe control subassembly 1.1. The needle shroud 7 has been moved furtherin the proximal direction P relative the front case 2.1 by an assemblyjig (not illustrated). In this state, the drive subassembly 1.2 may beassembled to the control subassembly 1.1. Subsequently, the assembly jigis removed and the needle shroud 7 translates in the distal direction Drelative to the front case 2.1 under the force of the shroud spring 8until the shroud rib 7.7 abuts the first plunger boss 10.1. The shroudbeam 7.1 is prevented from deflecting radially outward by the stop 2.12in the front case 2.1.

FIG. 15A is a longitudinal section of an exemplary embodiment of anautoinjector 1 according to certain aspects of the present inventionafter final assembly, and FIG. 15B is a schematic side view of anexemplary embodiment of an autoinjector 1 according to certain aspectsof the present invention after final assembly, wherein the case 2 isremoved for clarity.

In an exemplary embodiment, after the final assembly of the drivesubassembly 1.2 to the control subassembly 1.1, the autoinjector 1 maybe kept in temperature controlled environment (e.g., cold chain storage)to, for example, reduce creep in highly stressed components, e.g. underload from the drive spring 9.

An exemplary sequence of operation of an exemplary embodiment of theautoinjector 1 is as follows:

If applicable, the autoinjector 1 is removed from the packaging. Themedicament in the syringe 3 may be visually inspected through a viewingwindow (not shown), which can be a transparent part of the case 2 or acut-out in the case 2 aligned with the syringe 3.

The cap 11 is removed by pulling it in the distal direction D away fromthe case 2. As the cap 11 translates distally relative to the case 2,the bosses 11.2 on the cap 11 frictionally engage the protective needlesheath 5 and pull it off the needle 4 as the cap 11 is pulled in thedistal direction D, and the compliant beam 11.3 disengages the aperture7.6 in the needle shroud 7, as shown in FIG. 16. The compliant beam 11.3translates distally within the aperture 7.6 until it is no longerabutted radially by the radial stop 2.15 and engages a proximal surfaceof the aperture 7.6 (which may be ramped) and deflects radially todisengage the aperture 7.6. The syringe 3 is fixed in position relativeto the case 2, so pulling the cap 11 in the distal direction D does notcause any axial movement of the syringe 3. In an exemplary embodiment,the syringe 3 is also fixedly rotationally relative to the case 2 (e.g.,by an interference fit with the case 2 and/or the needle shroud 7).

FIG. 17A is a longitudinal section of an exemplary embodiment of theautoinjector 1 according to certain aspects of the present inventionprior to use. FIG. 17B is a schematic side view of an exemplaryembodiment of the autoinjector 1 according to certain aspects of thepresent invention prior to use, wherein the case 2 is removed forclarity.

When the cap 11 is removed, the needle shroud 7 is in a first extendedposition FEP relative to the case 2, protruding from the case 2 in thedistal direction D. The first extended position FEP is defined by thefirst plunger boss 10.1 abutting the shroud rib 7.7.

FIG. 18A is a longitudinal section of an exemplary embodiment of theautoinjector 1 according to certain aspects of the present inventionduring use. FIG. 18B is a schematic side view of an exemplary embodimentof the autoinjector 1 according to certain aspects of the presentinvention during use, wherein the case 2 is removed for clarity.

When the autoinjector 1 is pressed against an injection site, the needleshroud 7 translates proximally relative to the case 2 against thebiasing force of the shroud spring 8 from the first extended positionFEP to a retracted position RP, as shown in FIGS. 18A and 18B.

FIG. 19 shows an exemplary embodiment of the plunger release mechanism12 when the needle shroud 7 is in the retracted position RP. As theneedle shroud 7 translates from the first extended position FEP to theretracted position RP, the needle shroud 7 translates distally causingthe first plunger boss 10.1 to, starting from the position shown in FIG.8, ride along the shroud rib 7.7 until it is distal of the shroud rib7.7. When the first plunger boss 10.1 is distal of the shroud rib 7.7,the plunger 10 is no longer prevented from rotating in the secondrotational direction R2 relative to the case 2. Thus, the force of thedrive spring 9 on the plunger 10 and the engagement of the secondplunger boss 10.2 on the second angled surface 2.11 in the case slot2.3, causes the plunger 10 to rotate relative to the case 2. In anexemplary embodiment, the needle shroud 7 may include an aperture, arecess or a slot proximal of the shroud rib 7.7 to accommodate the firstplunger boss 10.1 when the needle shroud 7 is in the retracted positionRP and the plunger 10 rotates relative to the case 2.

In an exemplary embodiment, the shroud rib 7.7 (e.g., on thelongitudinal face 7.10) may include a resistance feature (e.g., aprojection, a ramp, a recess, etc.) adapted to abut the first plungerboss 10.1 as the needle shroud 7 translates from the first extendedposition FEP to the retracted position RP. When the first plunger boss10.1 abuts the resistance feature, a tactile feedback is provided in theform of increased resistance to pressing the autoinjector 1 against theinjection site. The tactile feedback may be used to indicate that needle4 will be inserted into the injection site upon further depression ofthe autoinjector 1 against the injection site. Prior to the needleshroud 7 reaching the retracted position RP, if the autoinjector 1 isremoved from the injection site, the needle shroud and reposition as theneedle shroud 7 will re-extend to its initial position under the forceof the shroud spring 8. When the needle shroud 7 is in the retractedposition RP, the needle 4 has been inserted into the injection site.Those of skill in the art will understand that a penetration depth ofthe needle 4 may be varied by, for example, limiting retraction of theneedle shroud 7 relative to the case 2, modifying an axial position ofthe syringe 3 relative to the case 2, modifying a length of the needle4, etc. Thus, the autoinjector 1 of the present invention may be usedfor subcutaneous, intra-dermal and/or intra-muscular injection.

FIG. 20A is a longitudinal section of an exemplary embodiment of theautoinjector 1 according to certain aspects of the present inventionduring use. FIG. 20B is a schematic side view of an exemplary embodimentof the autoinjector 1 according to certain aspects of the presentinvention during use, wherein the case 2 is removed for clarity.

When the plunger 10 has rotated a sufficient distance in the secondrotational direction R2 such that the second plunger boss 10.2disengages the case slot 2.3, the plunger 10 is free to translateaxially, under the force of the drive spring 9, relative to the case 2to push the stopper 6 to deliver the medicament M from the syringe 3through the needle 4.

In an exemplary embodiment, disengagement of the first plunger boss 10.1from the shroud rib 7.7 and/or the second plunger boss 10.2 from thecase slot 2.3 may provide an audible feedback indicating that deliveryof the medicament M has started. A viewing window in the case 2 mayallow for a visual feedback that the plunger 10 is advancing within thesyringe 3 for assessing the progress of displacement of the medicamentM.

FIG. 21A is a longitudinal section of an exemplary embodiment of theautoinjector 1 according to certain aspects of the present inventionafter use. FIG. 21B is a schematic side view of an exemplary embodimentof the autoinjector 1 according to certain aspects of the presentinvention after use, wherein the case 2 is removed for clarity.

When the autoinjector 1 is removed from the injection site, the needleshroud 7 translates distally relative to the case 2 from the retractedposition RP to a second extended position SEP under the biasing force ofthe shroud spring 8. In the second extended position SEP, the needleshroud 7 extends beyond a distal tip of the needle 4 and locks in anaxial position relative to the case 2. The second extended position SEPprevents needle-stick injury and may also indicate that the autoinjector1 has been used (because the needle shroud 7 cannot move proximally fromthe second extended position SEP). In an exemplary embodiment, in thesecond extended position SEP, the needle shroud 7 protrudes further,e.g. 2 mm, from the case 2 than in the first extended position FEP. Theneedle shroud 7 may include an indicia (e.g., a red ring, text, agraphic) on a portion which is visually accessible when the needleshroud 7 is in the second extended position SEP but not in the firstextended position FEP. The indicia may indicate that the autoinjector 1has been used.

FIG. 22 is a schematic view of an exemplary embodiment of the secondshroud lock mechanism 15 according to certain aspects of the presentinvention. As the needle shroud 7 translates from the retracted positionRP toward the second extended position SEP, the shroud beam 7.1 passesthe stop 2.12 in the distal direction D and relaxes radially outwardswhich is possible as the cap 11 is no longer present. In the secondextended position SEP, the needle shroud 7 cannot translate proximallyrelative to the case 2, because the shroud beam 7.1 abuts the stop 2.12.The needle shroud 7 is thus locked in the second extended position SEP.Extension of the needle shroud 7 distally beyond the second extendedposition SEP may be prevented by a shroud boss 7.2 on the needle shroud7 that abuts a case boss 2.8 on the case 2 (see FIG. 1).

FIGS. 23A to 23 E are schematic views of another exemplary embodiment ofa plunger release mechanism 12 of the autoinjector 1 according tocertain aspects of the present invention. The plunger release mechanism12 is arranged for preventing release of the plunger 10 prior toretraction of the needle shroud 7 relative to the case 2 and forreleasing the plunger 10 once the needle shroud 7 is sufficientlyretracted. In an exemplary embodiment, the plunger release mechanism 12comprises the plunger 10, the rear case 2.2, and the needle shroud 7interacting with each other. In an exemplary embodiment, the needleshroud 7 is limited to axial movement relative to the case 2, and theplunger 10 can translate axially and rotate relative to the case 2.

In an exemplary embodiment, the plunger 10 comprises a first plungerboss 10.1 adapted to engage a shroud rib 7.7 on the needle shroud 7 anda second plunger boss 10.2 adapted to engage a case slot 2.3 in the case2, and a plunger rib 10.3 adapted to engage the shroud rib 7.7 on theneedle shroud 7. In an exemplary embodiment, the shroud rib 7.7comprises a proximal face 7.8 adapted to engage the plunger rib 10.3,and a distal face 7.9 adapted to engage the first plunger boss 10.1. Inan exemplary embodiment, the case slot 2.3 comprises a first angledsurface 2.9 adapted to apply a rotational force in a first rotationaldirection R1 to the second plunger boss 10.2, a wall 2.10 adapted toabut the second plunger boss 10.2 to limit rotation of the plunger 10relative to the case 2 in the first rotational direction R1, and atransversal surface 2.16.

FIG. 23A is a schematic view of an exemplary embodiment of the plungerrelease mechanism 12 of the autoinjector 1 according to certain aspectsof the present invention during assembly of the drive subassembly 1.2.

In an exemplary embodiment of an assembly process of the drivesubassembly 1.2, the plunger 10 with the drive spring 9 is inserted intothe rear case 2.2. When the second plunger boss 10.2 is axially alignedwith the case slot 2.3, the plunger 10 is rotated in the firstrotational direction R1 until the second plunger boss 10.2 is moved intothe case slot 2.3 until it abuts the wall 2.10. In this position, thefirst angled surface 2.9 prevents the second plunger boss 10.2 frommoving in the second rotational direction R2, and thus prevents theplunger 10 from rotating relative to the case 2.

After a syringe 3 (with the protective needle sheath 5 disposed on theneedle 4) is inserted into the control assembly 1.1, the drivesubassembly 1.2 is coupled to the control subassembly 1.1. In anexemplary embodiment, a pair of resilient beams 2.13 (shown in FIG. 1B)on the rear case 2.2 is adapted to snap into recesses 2.14 (shown inFIG. 3) in the front case 2.1 to lock the drive subassembly 1.2 to thecontrol subassembly 1.1. FIG. 23B shows the drive assembly 1.2 beingcoupled to the control subassembly 1.1, wherein the needle shroud 7translates proximally (e.g., by use of an assembly jig) causing theshroud rib 7.7 to abut the plunger rib 10.3. As shown in FIG. 23C, asthe shroud rib 7.7 pushes plunger rib 10.3, the angle of the plunger rib10.3 causes the plunger 10 to rotate relative to the case 2 in thesecond rotational direction R2, and the second plunger boss 10.2 ridesalong the first angled surface 2.9 onto the transversal surface 2.16.

As shown in FIG. 23D, when the needle shroud 7 is released (e.g., byremoving the assembly jig), the needle shroud 7 translates in the distaldirection D relative to the case 2 under the force of the shroud spring8 until the shroud rib 7.7 abuts the first plunger boss 10.1. Forexample, the distal face 7.9 of the shroud rib 7.7 may abut the firstplunger boss 10.1 and maintain the needle shroud 7 in an axial positionrelative to the case 2. The second plunger boss 10.2 is prevented fromdisengaging the case slot 2.3 as it abuts the transversal surface 2.16in the distal direction D.

FIG. 23E shows an exemplary embodiment of the plunger release mechanism12 when the needle shroud 7 is in the retracted position RP. As theneedle shroud 7 translates from the first extended position FEP to theretracted position RP, the needle shroud 7 translates distally causingthe shroud rib 7.7 to, starting from the position shown in FIG. 23D,ride along the plunger rib 10.3 thereby rotating the second plunger boss10.2 in the second rotational direction R2 along the transversal surface2.16 until the second plunger boss 10.2 disengages the case slot 2.3thus releasing the plunger 10. Then, under the force of the drive spring9, the plunger 10 translates axially relative to the case 2 to deliverthe medicament M from the syringe 3. In this exemplary embodiment, atactile feedback may be provided in the form of an increase inresistance when the needle shroud 7 abuts and pushes against the plungerrib 10.3. The tactile feedback may indicate that needle insertion is orwill commence, or medicament delivery will be initiated, if theautoinjector 1 is pressed further against the injection site.

In an exemplary embodiment the transversal surface 2.16 could bereplaced by or comprise a concave shape for preventing inadvertentrelease of the plunger 10.

In another exemplary embodiment, the plunger 10 may not have the firstplunger boss 10.1, the plunger rib 10.3 may be disposed at differentangle than as described above, and the case slot 2.3 may not be angledrelative to a transverse axis of the case 2. In this exemplaryembodiment, when the autoinjector 1 is assembled, the plunger 10 ismaintained in axial position relative to the case 2, because the secondplunger boss 10.2 engages the case slot 2.3. However, the case slot 2.3may not impart any rotational force on the second plunger boss 10.2 (or,in another exemplary embodiment, the case slot 2.3 may be angled toimpart a rotational force on the second plunger boss 10.2 in the firstrotational direction R1 to ensure that the second plunger boss 10.2 doesnot disengage the case slot 2.3 inadvertently).

FIGS. 24A and 24B show different longitudinal sections of anotherexemplary embodiment of the autoinjector 1. The syringe, the needle andthe protective needle sheath are not shown for clarity. The illustratedembodiment may be arranged basically corresponding to the preciouslydescribed embodiments. The following description therefore predominantlydeals with the differences of the embodiment of FIGS. 24A and 24B to theprevious ones. A cap 11 may be removably disposed at a distal end of thecase 2. The cap 11 may include an element (e.g., a barb, a hook, anarrowed section, etc.) arranged to engage the protective needle sheath,the case 2 and/or a needle shroud 7 telescoped within the case 2. Theillustrated cap 11 does not comprise grip features. However, the cap 11of FIGS. 24A and 24B may likewise comprise the grip features of thepreviously described embodiments for facilitating removal of the cap 11(e.g., by twisting and/or pulling the cap relative to the case 2).

In an exemplary embodiment, a plunger release mechanism may be arrangedfor preventing release of the plunger 10 prior to retraction of theneedle shroud 7 relative to the case 2 and for releasing the plunger 10once the needle shroud 7 is sufficiently retracted. The plunger releasemechanism is not shown in FIGS. 24A and 24B for clarity. However, aplunger release mechanism 12 such as the ones illustrated in theprevious figures may be applied in the embodiment of FIGS. 24A and 24B.

In an exemplary embodiment, a first shroud lock mechanism 14 is arrangedto prevent retraction of the needle shroud 7 relative to the case 2 whenthe cap 11 is in place, thereby avoiding unintentional activation of theautoinjector 1 (e.g., if dropped, during shipping or packaging, etc.).The first shroud lock mechanism 14 may comprise one or more compliantbeams 11.3 on the cap 11 and a respective number of apertures 7.6 in theneedle shroud 7 adapted to receive each of the compliant beams 11.3.When the cap 11 is attached to the autoinjector 1, the compliant beams11.3 abut a radial stop 2.15 on the case 2 which prevents the compliantbeams 11.3 from disengaging the apertures 7.6. Other than in thepreviously described embodiments the apertures 7.6 do not permit alimited axial movement of the cap 11 relative to the shroud 7. When thecap 11 is attached to the autoinjector 1, axial movement of the cap 11in the proximal direction P relative the case 2 is limited by the cap 11abutting the case 2. When the cap 11 is pulled in the distal direction Drelative to the case 2, the compliant beams 11.3 may abut an edge of theaperture 7.6 and deflect to disengage the aperture 7.6, allowing forremoval of the cap 11 and the protective needle sheath attached thereto.In an exemplary embodiment, the compliant beams 11.3 and/or theapertures 7.6 may be ramped to reduce force necessary to disengage thecompliant beams 11.3 from the apertures 7.6. The cap furthermorecomprises at least one compliant case beam 11.6 adapted to engage in arespective number of apertures 2.16 in the case 2. When the cap 11 ispulled in the distal direction D relative to the case 2, the compliantcase beams 11.6 may abut an edge of the aperture 2.16 and deflect todisengage the aperture 2.16, allowing for removal of the cap 11 and theprotective needle sheath attached thereto. In an exemplary embodiment,the compliant case beams 11.6 and/or the apertures 2.16 may be ramped toreduce force necessary to disengage the compliant case beams 11.6 fromthe apertures 2.16.

A second shroud lock mechanism 15 is adapted to lock the needle shroud 7in an axial position relative to the case 2 after the autoinjector 1 hasbeen removed from the injection site. In an exemplary embodiment, thesecond shroud lock mechanism 15 comprises at least one compliant shroudbeam 7.1 on the needle shroud 7 adapted to proximally abut a stop 2.12on the case 2 after the autoinjector 1 has been removed from theinjection site. The abutment of the shroud beam 7.1 on the stop 2.12prevents translation of the needle shroud 7 in the proximal direction Prelative to the case 2. In an exemplary embodiment the stop 2.12 may bearranged on a compliant beam 2.17 in the case 2 to facilitate theinitial assembly of the shroud 7. In an exemplary embodiment the shroud7 can be assembled without the syringe 3 present so that the beam 2.17with the stop 2.12 can deflect radially in and allows the shroud beam7.1 to pass. The syringe 3 is then inserted and subsequently inwardlysupports the beam 2.17 preventing it from deflecting radially inwardthus creating an immovable stop 2.12. This allows for dispensing withthe function of the cap illustrated in FIGS. 12 to 14.

In an exemplary embodiment, the autoinjector 1 may be formed from atleast two subassemblies, e.g., a control subassembly 1.1 and a drivesubassembly 1.2 such as the one shown in FIG. 4 and described in thecorresponding section above to allow for flexibility as to the time andlocation of manufacture of the subassemblies 1.1, 1.2 and final assemblywith the syringe 3.

In an exemplary embodiment, the control subassembly 1.1 comprises thecap 11, the needle shroud 7, the shroud spring 8 and the front case 2.1.To assemble the control subassembly 1.1, the shroud spring 8 is insertedinto the needle shroud 7, and the needle shroud 7 with the shroud spring8 is inserted into the front case 2.1. The cap 11 is arranged over thedistal end of the needle shroud 7 and engages both the needle shroud 7and the case 2 by the compliant beams 11.3, 11.6 being engaged in theapertures 7.6, 2.16. The shroud spring 8 is thus in an at least slightlyloaded state wherein the load is statically resolved between the case 2and the shroud 7 which are coupled through the compliant beams 11.3,11.6 on the cap 11. In an exemplary embodiment the force exerted by theshroud spring 8 in that state is in a range from 2 N to 10 N whereas aforce required to remove the cap 11 is greater, e.g. up to 25 N due tothe design of the compliant case beams 11.6. The compliant case beam11.6 is thus designed to safely resolve the force from the shroud spring8 and yet allow easy removal of the cap 11.

After a syringe with the protective needle sheath disposed on the needle(not illustrated) is inserted into the control assembly 1.1, the drivesubassembly 1.2 is coupled to the control subassembly 1.1. In anexemplary embodiment, a pair of resilient beams (not illustrated butsimilar to the ones shown in FIG. 1B) on the rear case 2.2 is adapted tosnap into recesses (not illustrated) in the front case 2.1 to lock thedrive subassembly 1.2 to the control subassembly 1.1. As the driveassembly 1.2 is coupled to the control subassembly 1.1, the needleshroud 7 does not have to be translated proximally by use of an assemblyjig as in the previously described embodiments.

Instead the shroud 7 is already in the correct position and the controlspring 8 is in the at least slightly loaded state. Coupling the driveassembly 1.2 to the control subassembly 1.1 thus causes the shroud rib7.7 to abut the plunger rib 10.3. As shown in FIG. 7, as the shroud rib7.7 pushes plunger rib 10.3, the angle of the plunger rib 10.3 causesthe plunger 10 to rotate relative to the case 2 in the second rotationaldirection R2, and the second plunger boss 10.2 rides along the firstangled surface 2.9 onto the second angled surface 2.11. When the secondplunger boss 10.2 is disposed on the second angled surface 2.11, theforce of the drive spring 9 imparts a rotational force on the plunger 10in the second rotational direction R2 due to the angle of the secondangled surface 2.11.

In an exemplary embodiment, after the final assembly of the drivesubassembly 1.2 to the control subassembly 1.1, the autoinjector 1 maybe kept in temperature controlled environment (e.g., cold chain storage)to, for example, reduce creep in highly stressed components, e.g. underload from the drive spring 9 and shroud spring 8.

As shown in FIG. 8, when the needle shroud 7 is released (e.g., by auser pulling the cap 11 in the distal direction D thereby disengagingthe compliant case beams 11.6 from the respective apertures 2.16 in thecase 2 while the first compliant beams 11.3 remain engaged in theapertures 7.6 within the shroud 7), the needle shroud 7 translates inthe distal direction D relative to the case 2 under the force of theshroud spring 8 until the shroud rib 7.7 abuts the first plunger boss10.1. For example, the distal face 7.9 of the shroud rib 7.7 may abutthe first plunger boss 10.1 and maintain the needle shroud 7 in an axialposition relative to the case 2. The second plunger boss 10.2 isprevented from disengaging the case slot 2.3, because the shroud rib 7.7prevents the plunger 10 from rotating in the second rotational directionR2 relative to the case 2. For example, the longitudinal face 7.10 ofthe shroud rib 7.7 abuts the first plunger boss 10.1 to prevent rotationof the plunger 10. In this configuration, movement of the needle shroud7 in the proximal direction P relative to the case 2 is restricted,because the radial stop 2.15 prevents the compliant beam 11.3 fromdisengaging the aperture 7.6 and the rib 11.4 on the cap 11 proximallyabuts the front case 2.1. The axial position of the shroud 7 defined bythe distal face 7.9 and the first plunger boss 10.1 may be such that theshroud beam 7.1 does not travel distally beyond the stop 2.12 in thefront case 2.1 in that state.

A further sequence of operation of the embodiment of the autoinjector 1illustrated in FIGS. 24A and 24B may be corresponding to the sequence ofoperation described above for the embodiments shown in the previousfigures.

The embodiment of FIGS. 24A and 24B allows for assembling theautoinjector 1 without having to manipulate the shroud 7. An assemblyjig is therefore not required.

In an exemplary embodiment, a tamper strip (not shown) may be arrangedbetween the cap 11 and the front case 2.1 when the control subassembly1.1 is assembled. The tamper strip may be useful for quality assurance.

FIG. 25A is a schematic view of a distal end of an exemplary embodimentof an autoinjector 1 according to certain aspects of the presentinvention during assembly. The autoinjector 1 comprises a case 2 adaptedto hold a medicament container, such as a syringe.

In an exemplary embodiment, a cap 11 may be removably disposed at adistal end of the case 2. The cap 11 may include an element (e.g., abarb, a hook, a narrowed section, etc.) arranged to engage the case 2, aneedle shroud 7 telescoped within the case, and/or a protective needlesheath on the needle. The protective needle sheath may be rubber and/orplastic. In an exemplary embodiment, the protective needle sheath is arigid needle shield (RNS) formed from a rubber interior adapted toengage the needle with a plastic exterior at least partially covering anouter portion of the rubber interior. The cap 11 may comprise gripfeatures 11.5 for facilitating removal of the cap 11 (e.g., by twistingand/or pulling the cap 11 relative to the case 2). In an exemplaryembodiment, the grip features 11.5 may include one or more ribs, ridges,projections, bumps, notches, textured surfaces, or an overmolded coating(rubber, elastic, etc.), etc.

In an exemplary embodiment, a shroud spring 8 is arranged to bias theneedle shroud 7 distally toward an extended position relative to thecase 2. During use, the device 1 is pressed against an injection sitecausing the needle shroud 7 to move proximally relative to the case 2 toa retracted position against the biasing force of the shroud spring 8.

In an exemplary embodiment, a sheath removal mechanism 13 is arranged toremove the protective needle sheath from the medicament container onremoval of the cap 11 from the autoinjector 1. The sheath removalmechanism 13 may comprise one or more compliant sheath removal beams11.7 on the cap 11 adapted to engage the protective needle sheath.Typically, the sheath removal beams 11.7 extend in a proximal directionP from a distal face 11.10 of the cap 11 or are part of an internalsleeve extending in the proximal direction P from a distal face 11.10 ofthe cap 11. The compliant sheath removal beams 11.7 comprise respectiveinward ledges 11.8. When the compliant sheath removal beams 11.7 arerelaxed the ledges 11.8 provide a clearance between them smaller than adiameter of a protective needle sheath. In an exemplary embodiment anassembly tool may be inserted in an axial direction through an opening11.11 in the distal face 11.10 of the cap 11. FIG. 25B is a schematicview of an exemplary embodiment of the cap 11. The opening 11.11 isshaped similar to a keyhole such that an assembly tool may be insertedoff centre and engage between at least two of the sheath removal beams11.7 without blocking the path for a protective needle sheath duringinsertion.

In another exemplary embodiment one or more lateral apertures 11.9 arearranged in a lateral area of the cap 11 to allow insertion of anassembling tool. Corresponding lateral apertures 2.6, 7.3 may likewisebe arranged in the case 2 and the needle shroud 7 in such a manner thata set of lateral apertures 11.9, 2.6, 7.3 respectively aligns when thecap 11 is attached to the case 2.

The cap 11 is assembled to the autoinjector 1 by being moved in aproximal direction P relative to the needle shroud 7. When the cap 11 isbeing attached to the autoinjector 1, the sheath removal beams 11.7 areinserted into the needle shroud 7 which is sufficiently wide to allowthis.

When the cap 11 is attached to the autoinjector 1, axial movement of thecap 11 in the proximal direction P relative the case 2 is limited by arib 11.4 on the cap 11 abutting the case 2.

FIG. 26 is a schematic view of the distal end of the autoinjector 1 withthe assembled cap 11 during insertion of a wedge shaped assembly tool 16through the opening 11.11 in the distal face 11.10. The wedge shapedassembly tool 16 engages between two of the sheath removal beams 11.7splaying them apart thereby deflecting them in a radial outwarddirection. This opens up the clearance defined by the inward ledges 11.8to an extent allowing a protective needle sheath to pass through. In anexemplary embodiment the wedge shaped assembly tool 16 can also bearranged to displace the shroud 7 axially in the same motion enablingthe engagement of the second shroud lock mechanism 15 and priming of theplunger release mechanism 12.

FIG. 27 is a schematic view of the distal end of the autoinjector 1 withthe assembled cap 11 during assembly of a medicament container 3 with aprotective needle sheath 5. The medicament container 3 may be apre-filled medicament container and have a needle 4 arranged at a distalend. When the autoinjector 1 and/or the medicament container 3 areassembled, a protective needle sheath 5 may be removably coupled to theneedle 4. The protective needle sheath 5 may be a rubber needle sheathor a rigid needle sheath (which is composed of rubber and a full orpartial plastic shell). In other exemplary embodiments, the medicamentcontainer may be a cartridge which includes the medicament M and engagesa removable needle (e.g., by threads, snaps, friction, etc.).

The medicament container 3 and the protective needle sheath 5 areinserted into the case 2 and pushed in the distal direction D. Due tothe assembly tool 16 the clearance between the ledges 11.8 on thecompliant sheath removal beams 11.7 is wide enough to allow insertion ofthe protective needle sheath 5. In an exemplary embodiment the case 2may comprise an axial stop 2.5 limiting axial movement of the medicamentcontainer 3 within the case 2 in the distal direction D, e.g. byengaging a neck portion 3.1 of the medicament container 3.

FIG. 28 is a schematic view of the distal end of the autoinjector 1 withthe assembled cap 11, medicament container 3 and protective needlesheath 5. The assembly tool 16 is removed from the opening 11.11 in thedistal face 11.10 of the cap 11 such that the sheath removal beams 11.7are no longer splayed apart. Due to their beam stiffness the sheathremoval beams 11.7 relax radially inwards, the inward ledges 11.8 reducethe clearance between them and engage a proximal end 5.1 of theprotective needle sheath 5 thus axially coupling the cap 11 to theprotective needle sheath 5. In an exemplary embodiment the sheathremoval beams 11.7 are moulded in an inward deflected position whichensures they are always in intimate contact with the protective needlesheath 5 once the tool is removed. The wedge shaped assembly tool 16 isdesigned so that the sheath removal beams 11.7 are not deformed so faras to plastically yield. The contact point between the protective needlesheath 5 and the sheath removal beams 11.7 is arranged to minimise themoment acting to open the sheath removal beams 11.7 as the protectiveneedle sheath 5 is removed. Hence, gripping of the protective needlesheath 5 does not rely on radial compressive force exerted by the sheathremoval beams 11.7 but on a force exerted to the cap 11 in the distaldirection D relative to the case 2. In an exemplary embodiment of thewedge shaped assembly tool 16 may be arranged to splay the sheathremoval beams 11.7 in a direction perpendicular to the direction of theforce exerted to the cap 11 during cap removal.

When the cap 11 is pulled in the distal direction D relative to the case2, the ledges 11.8 engaged to the proximal end 5.1 of the protectiveneedle sheath 5 pull the protective needle sheath 5 off the medicamentcontainer 3.

In an exemplary embodiment, a force required to press the needle shroud7 may be approximately 2-12 N. Likewise, the mechanism may work with ahigher force.

In an exemplary embodiment, the syringe 3 used in the autoinjector 1 maybe a syringe capable of containing approximately 1 mL of the medicamentM. In another exemplary embodiment, the syringe 3 used in theautoinjector 1 may be a syringe capable of containing approximately 2 mLof the medicament M.

The autoinjector 1 according to certain aspects of the present inventionmay have an increased shelf-life compared to conventional autoinjectors,because, for example, only the plunger 10 is subjected to the relativelyhigh force of the drive spring 9.

The autoinjector 1 according to certain aspects of the present inventionmay be used as a platform as the drive spring 9 can be changed to altera force applied to the plunger 10, e.g., for delivering medicaments withdifferent viscosities drugs or reconstituted medicaments, or changing atime required to inject a dose of the medicament.

The cap 11 is suitable for being applied with any kind of injectiondevice or autoinjector.

The term “drug” or “medicament”, as used herein, means a pharmaceuticalformulation containing at least one pharmaceutically active compound,

wherein in one embodiment the pharmaceutically active compound has amolecular weight up to 1500 Da and/or is a peptide, a proteine, apolysaccharide, a vaccine, a DNA, a RNA, an enzyme, an antibody or afragment thereof, a hormone or an oligonucleotide, or a mixture of theabove-mentioned pharmaceutically active compound,

wherein in a further embodiment the pharmaceutically active compound isuseful for the treatment and/or prophylaxis of diabetes mellitus orcomplications associated with diabetes mellitus such as diabeticretinopathy, thromboembolism disorders such as deep vein or pulmonarythromboembolism, acute coronary syndrome (ACS), angina, myocardialinfarction, cancer, macular degeneration, inflammation, hay fever,atherosclerosis and/or rheumatoid arthritis,

wherein in a further embodiment the pharmaceutically active compoundcomprises at least one peptide for the treatment and/or prophylaxis ofdiabetes mellitus or complications associated with diabetes mellitussuch as diabetic retinopathy,

wherein in a further embodiment the pharmaceutically active compoundcomprises at least one human insulin or a human insulin analogue orderivative, glucagon-like peptide (GLP-1) or an analogue or derivativethereof, or exendin-3 or exendin-4 or an analogue or derivative ofexendin-3 or exendin-4.

Insulin analogues are for example Gly(A21), Arg(B31), Arg(B32) humaninsulin; Lys(B3), Glu(B29) human insulin; Lys(B28), Pro(B29) humaninsulin; Asp(B28) human insulin; human insulin, wherein proline inposition B28 is replaced by Asp, Lys, Leu, Val or Ala and wherein inposition B29 Lys may be replaced by Pro; Ala(B26) human insulin;Des(B28-630) human insulin; Des(B27) human insulin and Des(B30) humaninsulin.

Insulin derivates are for example B29-N-myristoyl-des(B30) humaninsulin; B29-N-palmitoyl-des(B30) human insulin; B29-N-myristoyl humaninsulin; B29-N-palmitoyl human insulin; B28-N-myristoyl LysB28ProB29human insulin; B28-N-palmitoyl-LysB28ProB29 human insulin;B30-N-myristoyl-ThrB29LysB30 human insulin; B30-N-palmitoyl-ThrB29LysB30human insulin; B29-N-(N-palmitoyl-Y-glutamyl)-des(B30) human insulin;B29-N-(N-lithocholyl-Y-glutamyl)-des(B30) human insulin;B29-N-(ω-carboxyheptadecanoyl)-des(B30) human insulin andB29-N-(ω-carboxyheptadecanoyl) human insulin.

Exendin-4 for example means Exendin-4(1-39), a peptide of the sequenceH-His-Gly-Glu-Gly-Thr-Phe-Thr-Ser-Asp-Leu-Ser-Lys-Gln-Met-Glu-Glu-Glu-Ala-Val-Arg-Leu-Phe-Ile-Glu-Trp-Leu-Lys-Asn-Gly-Gly-Pro-Ser-Ser-Gly-Ala-Pro-Pro-Pro-Ser-NH2.

Exendin-4 derivatives are for example selected from the following listof compounds:

-   H-(Lys)4-des Pro36, des Pro37 Exendin-4(1-39)-NH2,-   H-(Lys)5-des Pro36, des Pro37 Exendin-4(1-39)-NH2,-   des Pro36 Exendin-4(1-39),-   des Pro36 [Asp28] Exendin-4(1-39),-   des Pro36 [IsoAsp28] Exendin-4(1-39),-   des Pro36 [Met(O)14, Asp28] Exendin-4(1-39),-   des Pro36 [Met(O)14, IsoAsp28] Exendin-4(1-39),-   des Pro36 [Trp(O2)25, Asp28] Exendin-4(1-39),-   des Pro36 [Trp(O2)25, IsoAsp28] Exendin-4(1-39),-   des Pro36 [Met(O)14 Trp(O2)25, Asp28] Exendin-4(1-39),-   des Pro36 [Met(O)14 Trp(O2)25, IsoAsp28] Exendin-4(1-39), or-   des Pro36 [Asp28] Exendin-4(1-39),-   des Pro36 [IsoAsp28] Exendin-4(1-39),-   des Pro36 [Met(O)14, Asp28] Exendin-4(1-39),-   des Pro36 [Met(O)14, IsoAsp28] Exendin-4(1-39),-   des Pro36 [Trp(O2)25, Asp28] Exendin-4(1-39),-   des Pro36 [Trp(O2)25, IsoAsp28] Exendin-4(1-39),-   des Pro36 [Met(O)14 Trp(O2)25, Asp28] Exendin-4(1-39),-   des Pro36 [Met(O)14 Trp(O2)25, IsoAsp28] Exendin-4(1-39),-   wherein the group -Lys6-NH2 may be bound to the C-terminus of the    Exendin-4 derivative;-   or an Exendin-4 derivative of the sequence-   des Pro36 Exendin-4(1-39)-Lys6-NH2 (AVE0010),-   H-(Lys)6-des Pro36 [Asp28] Exendin-4(1-39)-Lys6-NH2,-   des Asp28 Pro36, Pro37, Pro38Exendin-4(1-39)-NH2,-   H-(Lys)6-des Pro36, Pro38 [Asp28] Exendin-4(1-39)-NH2,-   H-Asn-(Glu)5de5 Pro36, Pro37, Pro38 [Asp28] Exendin-4(1-39)-NH2,-   des Pro36, Pro37, Pro38 [Asp28] Exendin-4(1-39)-(Lys)6-NH2,-   H-(Lys)6-des Pro36, Pro37, Pro38 [Asp28] Exendin-4(1-39)-(Lys)6-NH2,-   H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Asp28]    Exendin-4(1-39)-(Lys)6-NH2,-   H-(Lys)6-des Pro36 [Trp(O2)25, Asp28] Exendin-4(1-39)-Lys6-NH2,-   H-des Asp28 Pro36, Pro37, Pro38 [Trp(O2)25] Exendin-4(1-39)-NH2,-   H-(Lys)6-des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28]    Exendin-4(1-39)-NH2,-   H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28]    Exendin-4(1-39)-NH2,-   des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28]    Exendin-4(1-39)-(Lys)6-NH2,-   H-(Lys)6-des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28]    Exendin-4(1-39)-(Lys)6-NH2,-   H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Trp(O2)25, Asp28]    Exendin-4(1-39)-(Lys)6-NH2,-   H-(Lys)6-des Pro36 [Met(O)14, Asp28] Exendin-4(1-39)-Lys6-NH2,-   des Met(O)14 Asp28 Pro36, Pro37, Pro38 Exendin-4(1-39)-NH2,-   H-(Lys)6-desPro36, Pro37, Pro38 [Met(O)14, Asp28]    Exendin-4(1-39)-NH2,-   H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Met(O)14, Asp28]    Exendin-4(1-39)-NH2,-   des Pro36, Pro37, Pro38 [Met(O)14, Asp28]    Exendin-4(1-39)-(Lys)6-NH2,-   H-(Lys)6-des Pro36, Pro37, Pro38 [Met(O)14, Asp28]    Exendin-4(1-39)-(Lys)6-NH2,-   H-Asn-(Glu)5 des Pro36, Pro37, Pro38 [Met(O)14, Asp28]    Exendin-4(1-39)-(Lys)6-NH2,-   H-Lys6-des Pro36 [Met(O)14, Trp(O2)25, Asp28]    Exendin-4(1-39)-Lys6-NH2,-   H-des Asp28 Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25]    Exendin-4(1-39)-NH2,-   H-(Lys)6-des Pro36, Pro37, Pro38 [Met(O)14, Asp28]    Exendin-4(1-39)-NH2,-   H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25, Asp28]    Exendin-4(1-39)-NH2,-   des Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25, Asp28]    Exendin-4(1-39)-(Lys)6-NH2,-   H-(Lys)6-des Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25, Asp28]    Exendin-4(S1-39)-(Lys)6-NH2,-   H-Asn-(Glu)5-des Pro36, Pro37, Pro38 [Met(O)14, Trp(O2)25, Asp28]    Exendin-4(1-39)-(Lys)6-NH2,

or a pharmaceutically acceptable salt or solvate of any one of theafore-mentioned Exendin-4 derivative.

Hormones are for example hypophysis hormones or hypothalamus hormones orregulatory active peptides and their antagonists as listed in RoteListe, ed. 2008, Chapter 50, such as Gonadotropine (Follitropin,Lutropin, Choriongonadotropin, Menotropin), Somatropine (Somatropin),Desmopressin, Terlipressin, Gonadorelin, Triptorelin, Leuprorelin,Buserelin, Nafarelin, Goserelin.

A polysaccharide is for example a glucosaminoglycane, a hyaluronic acid,a heparin, a low molecular weight heparin or an ultra low molecularweight heparin or a derivative thereof, or a sulphated, e.g. apoly-sulphated form of the above-mentioned polysaccharides, and/or apharmaceutically acceptable salt thereof. An example of apharmaceutically acceptable salt of a poly-sulphated low molecularweight heparin is enoxaparin sodium.

Antibodies are globular plasma proteins (˜150 kDa) that are also knownas immunoglobulins which share a basic structure. As they have sugarchains added to amino acid residues, they are glycoproteins. The basicfunctional unit of each antibody is an immunoglobulin (Ig) monomer(containing only one Ig unit); secreted antibodies can also be dimericwith two Ig units as with IgA, tetrameric with four Ig units liketeleost fish IgM, or pentameric with five Ig units, like mammalian IgM.

The Ig monomer is a “Y”-shaped molecule that consists of fourpolypeptide chains; two identical heavy chains and two identical lightchains connected by disulfide bonds between cysteine residues. Eachheavy chain is about 440 amino acids long; each light chain is about 220amino acids long. Heavy and light chains each contain intrachaindisulfide bonds which stabilize their folding. Each chain is composed ofstructural domains called Ig domains. These domains contain about 70-110amino acids and are classified into different categories (for example,variable or V, and constant or C) according to their size and function.They have a characteristic immunoglobulin fold in which two β sheetscreate a “sandwich” shape, held together by interactions betweenconserved cysteines and other charged amino acids.

There are five types of mammalian Ig heavy chain denoted by α, δ, ε, γ,and μ. The type of heavy chain present defines the isotype of antibody;these chains are found in IgA, IgD, IgE, IgG, and IgM antibodies,respectively.

Distinct heavy chains differ in size and composition; α and γ containapproximately 450 amino acids and δ approximately 500 amino acids, whileμ and ε have approximately 550 amino acids. Each heavy chain has tworegions, the constant region (C_(H)) and the variable region (V_(H)). Inone species, the constant region is essentially identical in allantibodies of the same isotype, but differs in antibodies of differentisotypes. Heavy chains γ, α and δ have a constant region composed ofthree tandem Ig domains, and a hinge region for added flexibility; heavychains μ and ε have a constant region composed of four immunoglobulindomains. The variable region of the heavy chain differs in antibodiesproduced by different B cells, but is the same for all antibodiesproduced by a single B cell or B cell clone. The variable region of eachheavy chain is approximately 110 amino acids long and is composed of asingle Ig domain.

In mammals, there are two types of immunoglobulin light chain denoted byλ and κ. A light chain has two successive domains: one constant domain(CL) and one variable domain (VL). The approximate length of a lightchain is 211 to 217 amino acids. Each antibody contains two light chainsthat are always identical; only one type of light chain, κ or λ, ispresent per antibody in mammals.

Although the general structure of all antibodies is very similar, theunique property of a given antibody is determined by the variable (V)regions, as detailed above. More specifically, variable loops, threeeach the light (VL) and three on the heavy (VH) chain, are responsiblefor binding to the antigen, i.e. for its antigen specificity. Theseloops are referred to as the Complementarity Determining Regions (CDRs).Because CDRs from both VH and VL domains contribute to theantigen-binding site, it is the combination of the heavy and the lightchains, and not either alone, that determines the final antigenspecificity.

An “antibody fragment” contains at least one antigen binding fragment asdefined above, and exhibits essentially the same function andspecificity as the complete antibody of which the fragment is derivedfrom. Limited proteolytic digestion with papain cleaves the Ig prototypeinto three fragments. Two identical amino terminal fragments, eachcontaining one entire L chain and about half an H chain, are the antigenbinding fragments (Fab). The third fragment, similar in size butcontaining the carboxyl terminal half of both heavy chains with theirinterchain disulfide bond, is the crystalizable fragment (Fc). The Fccontains carbohydrates, complement-binding, and FcR-binding sites.Limited pepsin digestion yields a single F(ab′)2 fragment containingboth Fab pieces and the hinge region, including the H—H interchaindisulfide bond. F(ab′)2 is divalent for antigen binding. The disulfidebond of F(ab′)2 may be cleaved in order to obtain Fab′. Moreover, thevariable regions of the heavy and light chains can be fused together toform a single chain variable fragment (scFv).

Pharmaceutically acceptable salts are for example acid addition saltsand basic salts. Acid addition salts are e.g. HCl or HBr salts. Basicsalts are e.g. salts having a cation selected from alkali or alkaline,e.g. Na+, or K+, or Ca2+, or an ammonium ion N+(R1)(R2)(R3)(R4), whereinR1 to R4 independently of each other mean: hydrogen, an optionallysubstituted C1-C6-alkyl group, an optionally substituted C2-C6-alkenylgroup, an optionally substituted C6-C10-aryl group, or an optionallysubstituted C6-C10-heteroaryl group. Further examples ofpharmaceutically acceptable salts are described in “Remington'sPharmaceutical Sciences” 17. ed. Alfonso R. Gennaro (Ed.), MarkPublishing Company, Easton, Pa., U.S.A., 1985 and in Encyclopedia ofPharmaceutical Technology.

Pharmaceutically acceptable solvates are for example hydrates.

Those of skill in the art will understand that modifications (additionsand/or removals) of various components of the apparatuses, methodsand/or systems and embodiments described herein may be made withoutdeparting from the full scope and spirit of the present invention, whichencompass such modifications and any and all equivalents thereof.

1. An autoinjector (1) comprising: a case (2) adapted to hold amedicament container having a needle (4); a needle shroud (7)telescopically coupled to the case (2) and movable between a firstextended position (FEP) relative to the case (2) in which the needle (4)is covered and a retracted position (RP) relative to the case (2) inwhich the needle (4) is exposed, a shroud spring biasing the needleshroud in a distal direction relative to the case; and a plunger (10)rotationally and slidably disposed in the case (2), the plunger (10)rotatable relative to the case (2) between a first rotational positionin which the plunger (10) is engaged to the case (2) and a secondrotational position in which the plunger (10) disengages the case (2),wherein the needle shroud (7) engages the plunger (10) to rotate theplunger (10) from the first rotational position to the second rotationalposition when the needle shroud (7) translates from the first extendedposition (FEP) to the retracted position (RP), the auto-injector (1)further comprising: a cap (11) removably coupled to the case (2),wherein the cap (11) includes at least one compliant case beam (11.6)adapted to releasably engage at least one aperture (2.16) in the case(2), wherein, when the cap (11) is moved in the distal direction (D)relative to the case (2), the at least one compliant beam (11.6)disengages the at least one aperture (2.16) in the case (2) and nolonger radially abuts the case (2), wherein a force required todisengage the at least one compliant case beam (11.6) from therespective aperture (2.16) is greater than a force exerted by the shroudspring when the compliant case beam (11.6) is engaged in the aperture(2.16).
 2. The autoinjector (1) according to claim 1, wherein the needleshroud (7) is movable to a second extended position (SEP) relative tothe case (2) in which the needle (4) is covered and the needle shroud(7) cannot translate relative to the case (2).
 3. The autoinjector (1)according to any one of the preceding claims, wherein the plunger (10)translates relative to the case (2) under force of a drive spring (9)when the plunger (10) is in the second rotational position and theneedle shroud (7) is in the retracted position (RP).
 4. The autoinjector(1) according to any one of the preceding claims, wherein the needleshroud (7) includes at least one compliant shroud beam (7.1) radiallyabutting the case (2) when the needle shroud (7) is in the firstextended position (FEP) and the retracted position (RP), wherein the atleast one compliant shroud beam (7.1) deflects radially when the needleshroud (7) is in the second extended position (SEP) and axially abutsthe case (2).
 5. The autoinjector (1) according to any one of thepreceding claims, wherein the plunger (10) includes a first plunger boss(10.1) adapted to engage a shroud rib (7.7) disposed on the needleshroud (7) and a second plunger boss (10.2) adapted to engage a caseslot (2.3) in the case (2).
 6. The autoinjector (1) according to claim5, wherein, when the plunger (10) is in the first rotational positionand the needle shroud (7) is in the first extended position (FEP), thefirst plunger boss (10.1) engages the shroud rib (7.7) and the secondplunger boss (10.2) engages the case slot (2.3).
 7. The autoinjector (1)according to claim 6, wherein, when the needle shroud (7) is in theretracted position (RP), the plunger (10) rotates from the firstrotational position to a second rotational position and disengages thecase slot (2.3).
 8. The autoinjector (1) according to any one of thepreceding claims, wherein the plunger (10) includes a plunger bossadapted to engage a case slot (2.3) in the case (2.3), and a plunger rib(10.3) adapted to engage a shroud rib (7.7) disposed on the needleshroud (7).
 9. The autoinjector (1) according to claim 8, wherein, whenthe plunger (10) is in the first rotational position and the needleshroud (7) is in the first extended position (FEP), the plunger bossengages the case slot (2.3).
 10. The autoinjector (1) according to claim9, wherein, when the needle shroud (7) translates from the firstextended position (FEP) to the retracted position (RP), the needleshroud (7) abuts the plunger rib (10.3) to rotate the plunger (10)relative to the case (2) from the first rotational position to a secondrotational position to disengage the plunger boss from the case slot(2.3).
 11. The auto-injector (1) according to one of the precedingclaims, wherein the cap (11) comprises: a distal face (11.10); at leastone compliant sheath removal beam (11.7) extending in a proximaldirection (P) from the distal face (11.10) and defining a space forreceiving the protective needle sheath (5), the at least one compliantsheath removal beam (11.7) including at least one ledge (11.8) adaptedto engage the protective needle sheath (5), wherein the at least onecompliant sheath removal beam (11.7) is disposed approximatelyperpendicular to the distal face (11.10) in a first position forengaging the protective needle sheath (5) and is disposed at anon-approximately perpendicular angle to the distal face (11.10) in asecond position for receiving the protective needle sheath (5).
 12. Theauto-injector (1) according to claim 11, wherein the at least onecompliant sheath removal beam (11.7) is biased toward the firstposition.
 13. The auto-injector (1) according to any one of the claim 11or 12, wherein the ledge (11.8) is adapted to engage proximally behind aproximal end (5.1) of the protective needle sheath (5) or into a recesswithin the protective needle sheath (5).
 14. The auto-injector (1)according to any one of the claims 11 to 13, further comprising one ormore openings (11.11) in a distal face (11.10) of the cap (11) or one ormore lateral apertures (11.9) arranged in a lateral area of the cap (11)to allow insertion of at least one assembling tool (16) for applying aforce to move the at least one compliant sheath removal beam (11.7) fromthe first position to the second position.